Weight won't budge.

Work out really hard? How much muscle definition have you gained as opposed to weight lost?

I'm 5'4" and my starting weight was 138. I started working out in May and got down to 126 lbs in June. I worked my butt off in July and actually GAINED weight. I'm at 134 right now. :-\

What in the world am I doing wrong?

Probably nothing. Depending on your frame size, you could well be at ideal weight already. For a 5'4" woman the ideal weight range is anything from 114-151lb. Exercising like a crazy woman is only going to build muscle which is heavier than fat by volume. When you are active (especially if you have increased your activity level), you should be paying more attention to your measurements than what the scales say.

It really depends on your goals on what you diet/exercise routine should be. Most of the diets floating around here are more for serious fat loss than anything. If I had access to your diary I would give you more input on the subject.

Diet and exercise is a really a hard thing to pin down when you are in the lower end of the BMI spectrum.

Don't be afraid to message or add me a friend if you need help.

i have the same problem. i weigh 130lbs and can NOT lose any more. i dropped to 125 for a short time but then went back to 130. everyone tells me to eat more but this just seems like it would make me gain weight

I'm 5'4" and my starting weight was 138. I started working out in May and got down to 126 lbs in June. I worked my butt off in July and actually GAINED weight. I'm at 134 right now. :-\
It's driving me crazy that I eat clean and workout really hard but my body doesn't reflect that.
My diet is perfect. I don't eat any processed food, fast food, sodas, etc. Most of my meals consist of lean protein and veggies. I tried changing the duration and intensity of my cardio. Nada. The weeks go by and my weight doesn't change.
What in the world am I doing wrong?

If all you did was cardio when you first lost weight, then the chances are that you lost lean muscle in the process. When that happens your actual metabolic rate became slower. So now with less lean muscle and the weight you've regained, it takes longer duration for you to burn the calories you used to burn if you still retained that lean muscle.
Add strength training. Lift heavy and hard. You may initially gain some weight for a week or two, but eventually that will subside and you'll see weight coming off and a much harder leaner body to boot. Works every time.

Talked to a personal trainer today. She said I'm most likely gaining muscle. She also told me to throw away my scale and start measuring.

PT is wrong. If you're in calorie deficit, then building muscle is highly unlikely.

Try being more active,l drink more water, have some green tea and increase your fiber. All of that will help speed up ur metabolism because it makes your body flush everything out. I also have fiber pills because when i first started out I had no idea of how to increase my fiber. Fiber one cereal and granola bars are good.

The body reacts differently at different ages. At 16, I was underweight at 95 pounds (same height as you, btw), but I danced every day (ballet training). It was unhealthy but I didn't know it, and even if I had, I didn't particularly care.

Fast forward to age 22. I started college then, gained to about 140 pounds and up three sizes. Lost the weight in the second year of college when I joined the dance department. BUT, I went to 125 and was the same size I was at 95 pounds.

Fast forward again to a bit later, I gained to 160. Again went back into dance more actively, lost to 140 pounds but was again the same size as I had been at 95 pounds.

I'm now a "woman of a certain age." I gained to 195 some years ago - and 5 dress sizes. LOST those 5 dress sizes in the past 3 years, and then some, but am holding at around 154 pounds. My weight HAS fluctuated between 146 and 154, but the size hasn't changed. I'm about as active now as I was at 16 - a bit more, because I'm doing weight training as well.

I've just found out I have an underactive thyroid and another issue, which is why I've gained instead of lost in the past month. So hopefully with medication, some of the extra pounds will come off and my toes will be happier when I'm doing pointe work. The little ring around the middle might also go. We shall see....

I would say you're in likely the right range for your height, but if you've gained instead of lost, you might want to ask the doc for a thyroid check. I know I ate properly and exercised a LOT (and checked my net cals, etc.) but my metabolism isn't letting the fat or the weight go.

So my advice would be to ask for a check of the thyroid and make sure you're not underactive. Also ask the doc to evaluate your diet and exercise to see if you're doing anything that might be messing up the metabolic rate. It might turn out that all you need is more iodine in your diet. (That wasn't my problem, btw, but it might be if you're young and you don't take a comprehensive multivitamin).